Immune System: Phagocytes, Lymphocytes, Immunity and Vaccines
Immune System Components
Phagocytes: Ingest foreign microorganisms and cell remains through phagocytosis. Travel through blood vessels.
Lymphocytes: Identify pathogens and coordinate specific responses. Travel through blood and lymphatic vessels.
Nonspecific Immunity
Nonspecific immunity: A reaction to the presence of a foreign substance, protecting organisms against invasion that could cause pathology.
Steps:
- Phagocytes: Engulf and destroy foreign microorganisms (phagocytosis).
- Inflammation: Increases blood flow to the infected site to attract phagocytes.
Specific Immunity
Specific immunity: Triggered by the detection of a specific pathogen (selective).
Steps:
- Antibodies (activated lymphocytes): Proteins that specifically bind to the pathogen or toxins to deactivate or destroy them.
- Destroying (cytotoxic lymphocytes): Destroy the cells infected by the pathogens.
- Inducing memory (memory lymphocytes): Ability to remember and respond more quickly when re-exposed to the same pathogen.
Immune System Disorders
Immunodeficiencies
Failure of the body’s immune system, resulting in an ineffective immune response. Infectious diseases have a more serious effect on immunodeficient people.
Causes: Poor nutrition, obesity, use of drugs, later stage of life.
Examples: Multiple sclerosis, AIDS, leukemia.
Autoimmunity
Impairment of the immune response, where the immune system acts against the body’s own cells. Immune cells identify cells from the same body as foreign and attack them as if they were pathogens.
Causes: Genetic factors.
Examples: Diabetes, lupus, psoriasis.
Allergies
An abnormal immune response to the presence of a foreign substance. When the body detects an allergen, it produces histamine, followed by signs of inflammation and skin rashes.
Notes: Allergies are random; people are allergic to a range of allergens, such as substances present in cat saliva, peanuts, pollen, and certain medications.
Stages of Infectious Disease
Incubation: Time between when the pathogen enters and the first symptoms. Multiplication of the pathogen.
Illness: Time from the onset of symptoms and signs of the disease. Discomfort, immune system activation, medical treatment.
Convalescence: Period once the pathogen has been eliminated. The body’s repair of damage caused by the infection.
Vaccines
Vaccines: Consist of inducing immune memory against specific pathogens without the organism developing the infectious disease.
Composition: Fragments or nonvirulent forms of a pathogen (attenuated or weakened pathogen).
Mechanism: Specific immune response. Lymphocytes will recognize the pathogen and generate memory.
Prevention and mitigation: Effective and quick immune response to face a future virulent form of the same pathogen.
Antibiotics
Antibiotics: Drugs that attack bacteria, destroying them or preventing them from multiplying. Specific antibiotics or broad-spectrum antibiotics.